Delhi's air turns twice each winter, and only the first turn gets the headlines. The first PM2.5 peak arrives with the stubble burning season and pushes the weekly average past 250 µg/m³—the 'severe' threshold on India's air quality index. That peak has been the subject of many TV debates. The reason it recurs is duller than the debates. A long-duration paddy variety leaves a farmer about 20 days to clear the field before wheat has to go in. Whether it burns depends on what else is available to them in those 20 days, and at what cost. Our work across Punjab and Haryana has been around these questions and behaviours. A survey of 1,500 farmers across 12 Haryana districts, and another on monitoring burning from space, is out later this week. Both are about where help is still needed. The second peak follows weeks later: winter biomass burning. Through the coldest weeks, wood, dung cakes, crop waste and whatever else is to hand are burnt for warmth—on construction sites, at guard posts in gated housing colonies, in homes in informal settlements with no affordable alternative. Thousands of small fires rather than one large source, which is what makes it hard to see and harder to govern. The rest of the year is the relatively cleaner stretch. Through the monsoon, weekly averages fall to around 27 µg/m³, inside the national 24-hour standard of 60, and about a tenth of what the city breathes at its November peak. Delhi has just had its October: the month everyone photographs, when the saptaparni comes into flower and the whole city smells of it. On this chart and outside our windows, that month is the end of the cleaner stretch, with the line already climbing. In a jugalbandi, two musicians play different instruments in the same composition. Neither leads, neither follows. This winter we will be talking about both halves of the answer: what a citizen can do, and what the state must. Stay with us. Check out our work on Clean Air: ceew.in/publications?field_f…